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* Experimenting with reduced gcc-lib
@ 2022-12-08 21:32 Julien Lepiller
  2022-12-15 14:34 ` Ludovic Courtès
  0 siblings, 1 reply; 4+ messages in thread
From: Julien Lepiller @ 2022-12-08 21:32 UTC (permalink / raw)
  To: guix-devel

[-- Attachment #1: Type: text/plain, Size: 1512 bytes --]

Hi Guix!

I had a look at gcc to try and reduce its footprint. I figured gcc-lib
contained shared and static libraries as well as support libraries for
gdb, many headers and compiler runtime, that are taking a lot of space
when they are not needed at runtime. Reducing its 33.4 MiB would help
create smaller guix packs, have smaller system and profile closures,
etc.

I figured gcc has a --with-slibdir option that is advertised as being
useful to specify a directory for the shared libraries. I decided to
use it and create a new output for the gcc package, shared-lib. In
fact, this option only installs libgcc_s.so in that output, and that's
the only thing required by most packages.

Attached is a patch that divides gcc-lib into gcc-static-lib and
gcc-shared-lib (not very good names, gcc-static-lib contains shared
libs too).

Before the patch we get:

guix size perl
total: 147.7 MiB

After the patch:

./pre-inst-env guix size perl
total: 114.5 MiB

This is because before the patch, gcc-lib is 33.4 MiB, and after the
patch gcc-shared-lib is only 0.2 MiB.

I don't want to push that patch as is, because libstdc++.so is still in
the gcc-static-lib output and will bring all the useless stuff with it.
C++ programs will bring back the remaining 33.2 MiB.

Another possible target is glibc, since the only useful bits in there
are libc.so and ld-linux.so (I think?). This could reduce the closure
of our packs by another ~40 MiB (I think our systems would still need
most of the content of this package).

[-- Attachment #2: 0001-gnu-gcc-Separate-lib-output.patch --]
[-- Type: text/x-patch, Size: 7976 bytes --]

From bff8567b0770455397d44f1ed304a67681b472c9 Mon Sep 17 00:00:00 2001
From: Julien Lepiller <julien@lepiller.eu>
Date: Thu, 8 Dec 2022 22:29:01 +0100
Subject: [PATCH] gnu: gcc: Separate lib output.

* gnu/packages/gcc.scm (gcc-4.7): Replace `lib' output with `static-lib'
  and `shared-lib'.
* gnu/packages/commencement.scm (gcc-boot0): Update accordingly.
---
 gnu/packages/commencement.scm |  6 +++---
 gnu/packages/gcc.scm          | 39 +++++++++++++++++++++++++----------
 gnu/tests/mail.trs            |  0
 3 files changed, 31 insertions(+), 14 deletions(-)
 create mode 100644 gnu/tests/mail.trs

diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index b4566b41cc..f3fce1750f 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -2853,7 +2853,7 @@ (define gcc-boot0
                         (lambda _ #t))))
                (add-after 'install 'symlink-libgcc_eh
                  (lambda* (#:key outputs #:allow-other-keys)
-                   (let ((out (assoc-ref outputs "lib")))
+                   (let ((out (assoc-ref outputs "static-lib")))
                      ;; Glibc wants to link against libgcc_eh, so provide
                      ;; it.
                      (with-directory-excursion
@@ -3417,7 +3417,7 @@ (define glibc-final
    ;; if 'allowed-references' were per-output.
    (arguments
     `(#:allowed-references
-      (,(gexp-input gcc-boot0 "lib")
+      (,(gexp-input gcc-boot0 "shared-lib")
        ,(kernel-headers-boot0)
        ,static-bash-for-glibc
        ,@(if (hurd-system?)
@@ -3523,7 +3523,7 @@ (define gcc-final
      `(#:guile ,%bootstrap-guile
        #:implicit-inputs? #f
 
-       #:allowed-references ("out" "lib" ,zlib-final
+       #:allowed-references ("out" "shared-lib" "static-lib" ,zlib-final
                              ,glibc-final ,static-bash-for-glibc)
 
        ;; Things like libasan.so and libstdc++.so NEED ld.so for some
diff --git a/gnu/packages/gcc.scm b/gnu/packages/gcc.scm
index bb154cac62..010c6102a0 100644
--- a/gnu/packages/gcc.scm
+++ b/gnu/packages/gcc.scm
@@ -106,8 +106,16 @@ (define-public gcc-4.7
                        '("CC"  "CXX" "LD" "AR" "NM" "OBJDUMP" "RANLIB" "STRIP")
                        '("gcc" "g++" "ld" "ar" "nm" "objdump" "ranlib" "strip"))
                   '()))))
+         (static-libdir
+          (let ((base '(or (assoc-ref outputs "static-lib")
+                           (assoc-ref outputs "out"))))
+            (lambda ()
+              ;; Return the directory that contains lib/libgcc_s.so et al.
+              (if (%current-target-system)
+                  `(string-append ,base "/" ,(%current-target-system))
+                  base))))
          (libdir
-          (let ((base '(or (assoc-ref outputs "lib")
+          (let ((base '(or (assoc-ref outputs "shared-lib")
                            (assoc-ref outputs "out"))))
             (lambda ()
               ;; Return the directory that contains lib/libgcc_s.so et al.
@@ -138,6 +146,12 @@ (define-public gcc-4.7
                      ,(string-append "--with-gxx-include-dir="
                                      (assoc-ref %outputs "out")
                                      "/include/c++")
+                     ,(string-append "--libdir="
+                                     (assoc-ref %outputs "static-lib")
+                                     "/lib")
+                     ,(string-append "--with-slibdir="
+                                     (assoc-ref %outputs "shared-lib")
+                                     "/lib")
 
                      ,(let ((libc (assoc-ref %build-inputs "libc")))
                         (if libc
@@ -170,7 +184,8 @@ (define-public gcc-4.7
        ;; Separate out the run-time support libraries because all the
        ;; dynamic-linked objects depend on it.
        (outputs '("out"                    ;commands, etc. (60+ MiB)
-                  "lib"                    ;libgcc_s, libgomp, etc. (15+ MiB)
+                  "shared-lib"             ;libgcc_s, libgomp, etc. (5+ MiB)
+                  "static-lib"             ;object code libraries and internal data files of GCC. (10+ MiB)
                   "debug"))                ;debug symbols of run-time libraries
 
        (inputs (list gmp mpfr mpc libelf zlib))
@@ -216,6 +231,7 @@ (define-public gcc-4.7
             (add-before 'configure 'pre-configure
               (lambda* (#:key inputs outputs #:allow-other-keys)
                 (let ((libdir ,(libdir))
+                      (static-libdir ,(static-libdir))
                       (libc   (assoc-ref inputs "libc")))
                   (when libc
                     ;; The following is not performed for `--without-headers'
@@ -257,8 +273,8 @@ (define-public gcc-4.7
                        ;; below, make sure to update the relevant code in
                        ;; %gcc-static package as needed.
                        (format #f "#define GNU_USER_TARGET_LIB_SPEC \
-\"-L~a/lib %{!static:-rpath=~a/lib %{!static-libgcc:-rpath=~a/lib -lgcc_s}} \" ~a"
-                               libc libc libdir suffix))
+\"-L~a/lib %{!static:-rpath=~a/lib -L~a/lib %{!static-libgcc:-rpath=~a/lib -lgcc_s}} \" ~a"
+                               libc libc libdir libdir suffix))
                       (("#define GNU_USER_TARGET_STARTFILE_SPEC.*$" line)
                        (format #f "#define STANDARD_STARTFILE_PREFIX_1 \"~a/lib\"
 #define STANDARD_STARTFILE_PREFIX_2 \"\"
@@ -324,19 +340,20 @@ (define-public gcc-4.7
                   ;; and <http://bugs.gnu.org/20358>.
                   (substitute* "libstdc++-v3/src/Makefile.in"
                     (("^OPT_LDFLAGS = ")
-                     "OPT_LDFLAGS = -Wl,-rpath=$(libdir) "))
+                     (string-append
+                       "OPT_LDFLAGS = -Wl,-rpath=" libdir " ")))
 
-                  ;; Move libstdc++*-gdb.py to the "lib" output to avoid a
-                  ;; circularity between "out" and "lib".  (Note:
+                  ;; Move libstdc++*-gdb.py to the "static-lib" output to avoid a
+                  ;; circularity between "out" and "shared-lib".  (Note:
                   ;; --with-python-dir is useless because it imposes $(prefix) as
                   ;; the parent directory.)
                   (substitute* "libstdc++-v3/python/Makefile.in"
                     (("pythondir = .*$")
-                     (string-append "pythondir = " libdir "/share"
+                     (string-append "pythondir = " static-libdir "/share"
                                     "/gcc-$(gcc_version)/python\n")))
 
                   ;; Avoid another circularity between the outputs: this #define
-                  ;; ends up in auto-host.h in the "lib" output, referring to
+                  ;; ends up in auto-host.h in the "static-lib" output, referring to
                   ;; "out".  (This variable is used to augment cpp's search path,
                   ;; but there's nothing useful to look for here.)
                   (substitute* "gcc/config.in"
@@ -917,7 +934,7 @@ (define* (custom-gcc gcc name languages
     (name name)
     (outputs (if separate-lib-output?
                  (package-outputs gcc)
-                 (delete "lib" (package-outputs gcc))))
+                 (delete "shared-lib" (delete "static-lib" (package-outputs gcc)))))
     (native-search-paths search-paths)
     (properties (alist-delete 'hidden? (package-properties gcc)))
     (arguments
@@ -979,7 +996,7 @@ (define-public (make-libgccjit gcc)
   (package
     (inherit gcc)
     (name "libgccjit")
-    (outputs (delete "lib" (package-outputs gcc)))
+    (outputs (delete "static-lib" (delete "shared-lib" (package-outputs gcc))))
     (properties (alist-delete 'hidden? (package-properties gcc)))
     (arguments
      (substitute-keyword-arguments (package-arguments gcc)
diff --git a/gnu/tests/mail.trs b/gnu/tests/mail.trs
new file mode 100644
index 0000000000..e69de29bb2
-- 
2.38.1


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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-12-08 21:32 Experimenting with reduced gcc-lib Julien Lepiller
2022-12-15 14:34 ` Ludovic Courtès
2022-12-15 16:59   ` Julien Lepiller
2022-12-19 21:14     ` Ludovic Courtès

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